Satellites Can Now See Through Cloud Covers

Using funds from the American space agency and the US National Science Foundation (NSF), scientists at the University of Iowa were recently able to develop a new viewing technique for satellites, which enable the spacecraft to see through Earth's cloud cover.

Currently, spacecraft can only conduct measurements on our planet's pollution levels when the weather allows for it. But clouds are a shifty bunch, and they can literally crop out of nowhere when you least expect them. Scientists have been trying to address this satellite limitation for a long time.

Spacecraft operating at radio and microwave wavelengths can already see through cloud covers, but they cannot produce certain types of data. With the new technique, it will become a lot easier to measure how much pollutants – including soot and aerosols – are present in the atmosphere.

Additionally, spacecraft will soon be able to conduct this type of measurements at any time. Pollutant particles that reduce air quality also play important roles in determining local weather patterns, and can also adversely affect human health, exacerbating respiratory conditions such as asthma.

The UI team published details of its new remote sensing technology in the July 9 early online issue of the esteemed journal Proceedings of the National Academy of Sciences (PNAS).

“Particles in the atmosphere (aerosols) interact with clouds changing their properties. With this technique, we can use remote sensing observations from satellites to estimate these cloud properties in order to correct predictions of particle concentrations,” Pablo Saide explains.

“This is possible due to a numerical model that describes these aerosol-clouds interactions,” he adds. The expert is an environmental engineering PhD student and researcher at the UI Center for Global and Regional Research (CGRER).

“Unlike previous methods, this technique can directly improve predictions of near-surface, fine-mode aerosols – such as coal-fired electric generating plants and wood-fueled cooking fires – responsible for human health impacts and low-cloud radiative forcing (solar heating),” adds Greg Carmichael.

The expert, a coauthor of the PNAS paper, holds an appointment as a professor of chemical and biochemical engineering at the University of Iowa, and is also a co-director of the CGRER.

“This technique is also complementary to previous methods used, allowing the observing system to ‘see aerosols’ even under cloudy conditions,” he concludes.